There are in the art a number of patent documents which describe workpiece cleaners using roller brushes to scrub the workpieces. One example is laid-open Japanese patent specification S61-8734 (Toshio et al) which describes a transfer member that can move a plurality of workpieces through cleaning stations with washing liquid sprayed onto the workpieces. The workpieces are cleaned by a roller brush.
The workpieces, which are disc shaped with a central hole, is supported at the central hole by the transfer member. This may cause a problem of the cleanliness of central hole being compromise by contact of the transfer member.
Another prior art document, United States Patent No. 2007006406 (McEntee et al) describes a horizontal scrubber type cleaning system. The workpieces are moved along stations of rotating brushes on a conveyor belt. A well known problem with this system is the slippage which can occur between conveyor belt and workpieces. Also, these types of workpiece cleaners require a complicated and often cumbersome linkage system to control movement of the member.
Another prior art example is U.S. Pat. No. 5,893,381 (Terui) which is a scrubbing method in a running liquid. This method requires the workpieces to be moved along a bath of wash liquid on carriers. These carriers are immersed in wash liquid and must be made to move the workpieces in this state, thus necessitating specialized equipment in which to do so. Furthermore, the brushes are embedded in the scrubbing means and are difficult to replace.
Another example of a similarly disadvantaged invention is U.S. Pat. No. 7,155,767 which uses a pair of annular plate scrubbers to clean the workpiece by conveying the workpiece towards an opposite rotating scrubber.
There is still a need for equipment with which to transport the workpiece, and this is adds to cost as well as increases need for maintenance. Moreover, this invention does not allow for easy modification for a different sized workpiece.
Generally speaking, the cleaners of this kind requires in one form or another for the workpieces to be transported around to where they are needed. This usually involves cumbersome equipment that costs more and requires higher maintenance.
It is therefore desirable to have a workpiece cleaner apparatus and method which can eliminate the need for the moving carrier or edgewheel, whilst maintaining flexibility and ease of modification to accommodate different sizes of workpieces, as well as to reduce the risk of splashing of the cleaning fluid.